<[email protected]> wrote in message news:[email protected]... [...] > I'm trying to track the drift of my GPS clock RELATIVE to > the clock that I would have obtained without GPS (and vice versa).
If I understand you correctly, you want to generate a log with two timestamps on each entry: one free-running, one GPS-synced. You could _not_ run NTP on your test machine, and whenever a message is logged, fetch a timestamp from another machine that does run NTP. Microsecond accuracy on that machine is not very hard with a GPS clock, but getting it into the test machine with the same accuracy may be a bit of a problem. It's mostly a matter of having the transfer take about the same time each time; if a good timestamp always arrives in exactly thirty milliseconds, that's good, you can correct for that. Another avenue is to run NTP on the test machine but not let it touch the clock (or not let it believe the other NTP server or for that matter any other server; you want a free-running clock). You still need the GPS-synchronised other NTP server, but running NTP on the test machine gives you easy, continuous, and fast access to an estimate of the current error in the local, free-running clock, and thus an idea of what the 'real' time is. > My final goal is to convert a series of gps timestamps to the > equivalent unsychronized timestamps. Whereas I propose doing it the other way around. It produces the same information and it's easier to do. I think. Groetjes, Maarten Wiltink _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
